The present invention relates to a kit of elements of sheet material for flashing a quadrangular roof-penetrating element, for instance a window, a chimney, a ventilating duct or the like, in an inclined roof with a substantially plane surface, which material comprises one side suited for fastening to the roof surface by gluing, adhesion, welding or the like and a second weather-proof side.
The invention further relates to a method for flashing a quadrangular roof penetrating element, for instance a window, a chimney, a ventilating duct or the like, in an inclined roof with a substantially plane surface, in particular made from concrete, by means of a kit of elements of the type mentioned above.
Danish patent No. 98982 discloses a "method for flashing corners on chimneys, dome light frames and the like protrusions on roofs with roofing felt and a bituminous sheet for use in such flashing". According to this publication, the corners of the protrusion (the roof penetrating element) are first covered by means of small textile reinforced bituminous sheets which are slit for the formation of flaps which are bent and melted together to form closed corners, following which bituminous felt sheets are mounted, said sheets extending on the sides of the roof penetrating elements forward to but not around the corners. It is said in this patent that it is known to use roofing felt strips extending from the roof surface and somewhat upwards along a side surface of the roof penetrating element, in which the part of the roofing felt extending upwards along the vertical surface at its edge is bent around the edge, a splitting of the strip being made until the place, where the vertical edge meets the roof surface.
The above-mentioned method is further known from a working instruction from the firm Icopal. From the same working instruction it is known, on basis of a measurement of the dimensions of the roof penetrating elements, to cut elements from roofing felt, whereby cuts are made at the ends of some of the elements, said cuts extending in extension of premeditated folding lines, to make it possible to fold end portions of bent up portions of the elements around the corners of the roof penetrating element.